Surgical devices for small bone fracture surgery

ABSTRACT

Small bone surgical nail devices and methods for use m small hone fracture surgeries, for example, clavicle fracture surgery. The systems and methods can include a nail device with specific design features including, but not limited to differing designs, geometries, and configurations in multiple zones of the device, an associated optional end cap, and/or optional locking screws.

BACKGROUND Technical Field

Embodiments described herein relate to innovative surgical devices andmethods that can be used to significantly improve clinical outcomes forpatients while reducing healing times, reducing costs, and increasingsurgical accuracy in small bone fracture surgeries. Embodiments of smallbone surgical devices and methods can be particularly impactful on smallbone fracture surgeries, including, but not limited to, claviclefracture surgery.

Background

Fractures of small bones, for example, clavicle fractures, are commonand may require surgery. Clavicle fractures are one of the most commonfractures. However, current repair devices are insufficient. The devicesused to repair clavicle fractures or other small bone fractures includeeither nails or plates. Plates can be large and overbearing and canprotrude from the skin. This can cause large incisions and scars whichcan lead to numbness and tingling post-surgery. Additionally, removing aplate post-surgery is very difficult. It can require longer proceduresthat are more expensive for every party involved. Current nail productscan be difficult to place and, after inserted, too often need to beremoved. More importantly, they can move excessively within the bone(e.g., migration, rotation).

SUMMARY

Certain embodiments of the application address a need for a surgicalnail system that will prevent migration and rotation while allowing forease and efficiency of insertion. In some aspects, a clavicle nailfixation system is provided, the system comprising a nail sized forpositioning within a clavicle bone. The nail comprises an elongate shafthaving a proximal end and a distal end, the nail comprising multiplezones along its length having various cross-sectional geometries.

The system of the preceding paragraph may also include any combinationof the following features described in this paragraph, among othersdescribed herein. The system can include the nail comprising an end zoneat its distal end having a first cross-sectional shape and a shaft zoneproximal to the end zone having a second cross-sectional shape, whereinthe first cross-sectional shape is different from the secondcross-sectional shape. The system can include a transition zone betweenthe end zone and the shaft zone, wherein the transition zone has a thirdcross-sectional shape. The system can include at least the end zonehaving a non-circular cross section. The system can include the endzone, transition zone, and shaft zone comprising a non-circular crosssection. In some embodiments, the shaft zone has a largercross-sectional area than the end zone. In some embodiments, the shaftzone has a cross sectional area greater than or equal to a crosssectional area of the transition zone and wherein the cross sectionalarea of the transition zone is greater than or equal to a crosssectional area of the end zone. In some embodiments, the proximal end ofthe nail has a round-cross section. In some embodiments, the nailcomprises an anterior surface sized and configured to face an anteriorside of the clavicle bone and a posterior surface sized and configuredto face a posterior side of the clavicle bone, and wherein the nail isbent or curved toward either the anterior surface or the posteriorsurface. In some embodiments, at least a portion of either the anteriorsurface or the posterior surface is flat. In some embodiments, thedistal end of the nail has at least one sharp edge. In some embodiments,the end zone comprises a cutting geometry configured to create a paththrough the medullary canal of the bone, the cutting geometry comprisinga curvature on at least one edge of the end zone toward the distal endof the device configured to create a sharp distal end. In someembodiments, a distal portion of the nail has a cross-section with fourflat sides. In some embodiments, the nail has a first cross-section witha plurality of flat surfaces and a second cross-section with a singleflat surface, wherein the second cross section is proximal to the firstcross-section. In some embodiments, the transition zone is configured toprovide at least one transitional cross section between the firstcross-section with a plurality of flat surfaces and the secondcross-section with a single flat surface. The system can include an endcap at or configured to engage the proximal end of the nail. In someembodiments, the proximal end of the nail is externally threaded and adistal portion of the end cap is internally threaded for attachment tothe externally threaded proximal end. In some embodiments, the end capis crimped or welded onto the proximal end of the nail. In someembodiments, the end cap comprises a plurality of retractable andexpandable wings for engagement with bone. In some embodiments, aproximal portion of the end cap is internally threaded to receive ascrew extractor. The system can include one or more locking screws forengagement with the end cap or the nail.

In some aspects, a surgical device for use in small bone fracturesurgery comprises a surgical nail configured to be at least partiallysubmerged within a bone, the surgical nail comprising a distal end and aproximal end, the surgical nail comprising a first zone positioned atthe distal end of the surgical nail configured to be inserted into bone,the first zone comprising a non-circular cross section, the first zonehaving a first cross-sectional area, wherein the first zone comprises acutting geometry configured to create a path through the medullary canalof the bone, the cutting geometry comprising a curvature on at least oneedge of the first zone toward the distal end of the device configured tocreate a sharp distal end; a second zone comprising a non-circular crosssection and positioned proximal to the first zone, the second zonecomprising a second cross-sectional area; and a third zone comprising anon-circular cross section and positioned proximal to the second zone,the third zone comprising a third cross sectional area, wherein thethird cross sectional area comprises at least one flat edge configuredto allow the third zone to engage with the surrounding bone, wherein thesecond zone is configured to provide at least one transitional crosssection between the sharp distal end and the at least one flat edge ofthe third zone, and wherein the third cross-sectional area is greaterthan or equal to the second cross sectional area and the second crosssectional area is greater than or equal to the first cross sectionalarea.

BRIEF DESCRIPTION OF THE DRAWINGS

Various embodiments of the devices and methods of the present disclosureare described herein with reference to the drawings wherein:

FIG. 1 illustrates an embodiment of a small bone fracture systemincluding a nail, end cap, and locking system within a clavicle bone;

FIG. 2 illustrates of an embodiment of a small bone fracture systemincluding a nail, end cap, and locking system within a clavicle bone;

FIGS. 3A-G illustrate views of an embodiment of a small bone fracturesystem including a nail, end cap, and locking screw system;

FIGS. 4A-G illustrate views of an embodiment of a surgical nail;

FIG. 5 illustrates views of an embodiment of a surgical nail with crosssections D-D, C-C, B-B, and A-A;

FIG. 6 illustrates an embodiment of a surgical nail with thelateral/medial and posterior/anterior portions of the surgical nailshown;

FIG. 7 illustrates an embodiment of a small bone surgical nail systemwith multiple zones as shown with three distinct zones: the end zone;the transition zone; and the shaft zone;

FIG. 8 illustrates cross-sections of the end zone of the device that canbe used;

FIGS. 9A-B illustrate embodiments of designs of the surgical nail endzone with limited or no curvature and a distal end that is not dull;

FIG. 9C illustrate embodiments of a surgical nail system;

FIG. 10 illustrates embodiments of the cross sectional areas of thetransition zone;

FIGS. 11A-B show embodiments of the transition from the sharp to flatcross-section of the small bone surgical nail device;

FIGS. 12A-C illustrate embodiments of cross-sectional shapes for theshaft zone;

FIG. 13 illustrates an embodiment of the surgical nail system deviceadapted to receive at least one locking screw;

FIG. 14A illustrates an embodiment of the end cap secured to the end ofthe nail and the entire unit advanced into the bone;

FIG. 14B illustrates an embodiment of the end cap including anextraction end cap that has a screw pitch for later extraction;

FIG. 14C illustrates an embodiment of the end cap that can allow forextraction by a screw-in attachment;

FIG. 14D illustrates embodiments of alternate cross sectional geometriesfor the end cap;

FIG. 15A-D illustrates views of an embodiment of the end cap design withlocking wings;

FIG. 16A-D illustrates views of an embodiment of the end cap design withlocking wings;

FIG. 17 illustrates an embodiment of the screw for inserting into theend cap design with locking wings;

FIG. 18A-C illustrates embodiments of the end cap designs for the smallbone surgical nail system;

FIGS. 19A-19D illustrate views of an embodiment of the end cap designwith a tab and screw end cap locking system; and

FIG. 20 illustrates a clavicle fracture procedure with an embodiment ofthe surgical nail system.

DETAILED DESCRIPTION

Embodiments of the small bone surgical nail system can be used for smallbone fracture surgeries, for example clavicle fracture surgery. Thesmall bone surgical nail systems disclosed can be used in whole or inpart, with each element or aspect of the system being independentlyapplicable of each other. The system comprises a nail device withspecific design features including but not limited to differing designs,geometries, and configurations in multiple zones of the device, anassociated optional end-cap, and/or optional locking screws or lockingsystems. In some embodiments, the nail device can be made of a materialused for surgical implants and surgical nails including, but not limitedto, stainless steel and titanium and alloys thereof.

The small bone surgical nail system can have multiple zones as shown inat least FIGS. 1, 2, FIGS. 3A-G, FIGS. 4A-G, FIG. 5, FIG. 6, and FIG. 7.As illustrated in these figures, in some embodiments the device can varyin three distinct zone types: the end zone; the transition zone; and theshaft zone. The distinct zones can have unique geometries that canfacilitate insertion, improve rotational control, simplify extraction,create flexible lengths, and increase stability of the device. Themultiple zone device design, with particular attention to minor designdetails in each zone, is advantageous for small bone surgeries withinwhich the surgeon must operate with a small margin for error aroundlimited space and bone. As described further below, zones can be used invarying order and numbers, but describe the innovative design structureof a given nail system that provide improved surgical results on manylevels. As one example, the end zone of the device can comprise a distalend or distal tip of the device and is the first portion introduced intobone. The end zone can be the leading end as the device is passedthrough the bone, which may be proximal to a shaft zone. A transitionzone may be positioned between any two zones, for example, between theend zone and a shaft zone.

The small bone surgical nail system utilizes the device geometry withindifferent zones within the device that are designed to optimize surgery.In some embodiments, the nail device can include at least two zones. Thedesign of the nail is based on the individual zones as well as how eachzone of the device works with respect to one another (and hence, impactssurgery and healing). Described herein is a device with three or morezones, however, the device can be made of any number of zones greaterthan one.

Although not limited to this geometry, at least the first two zones(distal zones, e.g., the end zone and the transition zone) of the devicecan have non-circular cross-sections. In some embodiments, all zonescontain non-circular cross-sections. In some embodiments, along thelength of the nail from a distal end to a proximal end thecross-sectional area of each zone is greater than or equal to thecross-sectional area of the more distal zone. Depending on the bone orfracture being repaired, the nail can be entered through variouspositions within the body. For example, to repair a clavicle fracture,it is understood that the nail may enter the fractured clavicle fromeither the distal end of the clavicle at the shoulder or the proximalend of the clavicle at the sternum.

FIG. 1 illustrates a view of an embodiment of the small bone fracturesystem including a nail 10, an end cap 20 at a proximal end of the nail10, and the end cap has a winged locking system 80 within a claviclebone 5. As illustrated, the distal tip of the nail 10 is positioned onthe lateral side of the clavicle bone 5, and the proximal end of thenail 10 (where the end cap 20 and winged locking system 80 are located)is positioned on the medial side of the clavicle bone 5. The variousgeometries of the nail 10, as described further below, are positioned inthe clavicle bone to prevent rotation and movement within the bone.Additionally, an embodiment of an end cap and winged locking system arealso shown positioned within the clavicle bone and attached to themedial or proximal end of the surgical nail. The details of the wingedlocking system are described in more detail below.

The clavicle bones can also have an anterior side and a posterior side.The posterior side of the clavicle refers to the portion of the clavicledirected toward the back side of the body of the patient. The anteriorside of the clavicle refers to the portion of the clavicle directedtoward the front side of the body of the patient. The anterior side ofthe clavicle is the front of the clavicle bone as shown in FIG. 1. Theposterior side of the clavicle bone in FIG. 1 is not shown and would befacing into the page. The clavicle bone presents a double curvature. Thecurvature of the clavicle bone can include a convex anterior curve inthe medial half and a concave anterior curve in the lateral half of theclavicle.

As discussed in more detail below, the surgical nail can have varyinggeometries that ease insertion and prevent rotation of the surgicalnail. In some embodiments, the nail can include flat surfaces. In someembodiments, the flat surfaces can be aligned with and facing theposterior side of the clavicle bone. In some embodiments, the flatsurfaces can be aligned with and facing the anterior side of theclavicle bone. In some embodiments, the flat surfaces can be in morethan one portion of the nail and at least one flat surface can bealigned with and facing the anterior side of the clavicle bone and atleast one flat surface can be aligned with and facing the posterior sideof the clavicle bone. The illustrated clavicle bone shown in FIGS. 1 and2 is shown with the length of the bone aligning with an x-axis and ay-axis is perpendicular to the length of the clavicle bone and passesthrough the width of the bone from top to bottom. The z-axis passesthrough an anterior-posterior width of the clavicle bone and asillustrated in FIGS. 1 and 2 the z-axis goes into and out of the page.The clavicle bone has an S-shaped curvature that curves along the z-axisinto and out of the page as illustrated in FIGS. 1 and 2. The curvatureof the clavicle bone can include a convex anterior curve in the medialhalf and a concave anterior curve in the lateral half of the clavicle.

As shown in FIGS. 1 and 2, the nail can have an anterior and posteriorportion. The posterior portion of the nail refers to the portion of thenail directed toward the back side of the body of the patient when thedevice is implanted. The anterior portion of the nail refers to theportion of the nail directed toward the front side of the body of thepatient when the device is implanted. The shaft of the nail can have ananterior 100 and posterior 200 portion that defines the positioning ofthe nail within the clavicle bone or other small bone, with the medialend (or proximal end) 300 and the lateral end (or distal end) 400referring to the lateral side and medial side of the clavicle bone orother small bone. The posterior portion 200 of the nail 10 cannot beseen in FIG. 1 as the posterior portion 200 is facing into the page.

FIG. 2 illustrates another embodiment of the small bone fracture systemincluding a nail 10, an end cap 20 at a proximal end of the nail 10, andlocking screw system 30 within a clavicle bone 5. As illustrated, thedistal tip of the nail 10 is positioned on the lateral side of theclavicle bone 5, and the proximal end of the nail 10 (where the end cap20 and locking screw system 30 are located) is positioned on the medialside of the clavicle bone 5. The various geometries of the nail 10, asdescribed further below, are positioned in the clavicle bone to preventrotation and movement within the bone. Additionally, an embodiment of anend cap and locking screw are also shown positioned within the claviclebone and attached to the medial or proximal end of the surgical nail. Asdescribed previously, depending on the bone or fracture being repaired,the nail can be entered through various positions within the body. Forexample, to repair a clavicle fracture, it is understood that the nailmay enter the fractured clavicle from either the medial end of theclavicle at the sternum as described and shown with reference to FIGS. 1and 2 previously or the lateral end of the clavicle at the shoulder (notshown). In embodiments where the nail is entered from the lateral end ofthe clavicle, the nail geometry described herein can be reversed fromthe proximal to distal end of the nail from that shown and describedherein. Therefore, in such embodiments, the components and zonesdescribed on the proximal end of the nail would be on the distal end ofthe nail and the components and zones described on the distal end of thenail would be on the proximal end of the nail. Additionally, in suchembodiments, the end cap and lock screw can be positioned at the lateralend of the surgical nail once inserted into clavicle.

FIGS. 3A-G illustrates views of an embodiment of the small bone fracturesystem described above without the bone 5 being illustrated. As shown byFIGS. 1, 2, 3A-G, and 4A-G the curvature of the nail 20 can be utilizedto ease insertion of the nail 20 within the bone 5 with minimal damageto the surrounding bone as well as prevent movement once placed withinthe bone. In some embodiments, the curvature of the nail can curve alongthe z-axis, from anterior to posterior and/or posterior to anterior,mimicking the natural S-shaped curve of the clavicle bone. In someembodiments, as shown in FIGS. 3A-G and 4A-G the anterior side of thenail 10 can include a flat surface that faces the anterior surface ofthe clavicle bone. In some embodiments, the posterior side of the nailcan include a flat surface that faces the posterior surface of theclavicle bone. In some embodiments, both the anterior and posteriorsurfaces of the nail can include a flat surface. The placement of theflat surface on the anterior and/or posterior portions of the nail canease insertion of the nail into the clavicle bone. The flat surface onthe anterior and/or posterior portions of the nail can allow for thenail to bend or curve toward the anterior or posterior surface of theclavicle forming a bend or curve that mimics the S-shaped curvature ofthe clavicle bone along the z-axis. In some embodiments, the nail istitanium, which is soft and allows the nail to contour to the bone. Insome clavicle surgical procedures, the insertion point for the nail canbe a bit anterior and lateral to the medial end of the bone. This couldput the insertion point mostly past the first curvature of the S shapedclavicle bone. Therefore, in some embodiments, there may only be a needfor one bend or curvature in the nail device.

The end cap 20 as shown in FIGS. 3A-G can have a threaded portion in theinterior of the end cap as described in more detail below. The proximalend of the nail can also include a threaded portion complementary to theinternally threaded portion of the end cap 20. This allows the end cap20 to be screwed on to the proximal or medial end of the nail 10. Theend cap 20 can also include a locking screw 30 to assist in anchoringthe surgical nail system in the bone as described in detail herein.

FIGS. 4A-G illustrates further views of an embodiment of the surgicalnail as described above. The surgical nail as shown in FIGS. 4A-Gcomprises an elongated shaft that includes a proximal end 11. In someembodiments, the proximal end 11 can include an externally threadedportion. As illustrated in FIGS. 4A-G, the surgical nail can include anail tip 12 at the distal most end of the elongated shaft, and a centralshaft portion between the proximal and distal ends that includes variouscurvatures and cross-sections as described in more detail below. Forexample, a section 13 of the elongated shaft shown in FIGS. 4A-Gillustrates a curvature and non-circular cross-section of the nail.

FIG. 5 illustrates views of an embodiment of the surgical nail of FIG.4A-G with cross sections D-D, C-C, B-B, and A-A shown. Cross section D-Dincludes a cross section relatively closer to the distal end of the nail10, and the cross section A-A includes a cross section relatively closerto the proximal end of the nail 10. As can be seen in cross section D-Dthe non-circular cross-section of the distal end of the nail includesmore than one flat end 14, 15, 16, 17. As illustrated in the crosssection D-D, the flat ends meet to form sharp points or edges to helptunnel the nail through the bone. This configuration creates an anteriorpointed edge 100 and a posterior pointed edge 200 as shown in crosssection D-D. Cross section C-C and cross section B-B representadditional cross sections on the nail. Cross section C-C represents across section from a more proximal position on the nail than the crosssection from cross section D-D and the cross section B-B represents across section from a more proximal position on the nail than the crosssection C-C. Cross section C-C and cross section B-B includes a crosssection with a more rounded shape on the posterior side 200 of the nailthan cross section D-D but still maintaining a non-circular crosssection with at least one flat side. The cross section C-C represents anintermediate cross section between cross section D-D and cross sectionB-B and represents the transitional shape between the cross section D-Dand cross section B-B. Cross section C-C includes a rounded posteriorside 200 of the nail and a flat surface on the anterior side 100 of thenail. Cross section A-A represents a cross section at a proximal end ofthe nail (more proximal than cross section B-B). Cross section A-Aincludes a circular cross section. As seen in cross section C-C thetransitional shape can provide a smooth transition between cross sectionD-D to cross section B-B which can improve insertion and thenon-circular shape assists in preventing rotation and migration of thedevice as described in detail herein. In some embodiments, as shown inFIG. 5, the flat surfaces or less rounded surfaces of the shaft zone ofthe nail as shown in the cross section C-C and B-B can be positioned onthe anterior or posterior portions of the nail to assist in insertionand aid in guiding or predicting the curvature of the nail as describedherein. For example, FIGS. 5 and 6 show the one or more flat surface onthe anterior portion 100 of the shaft zone of the nail while theposterior portion 200 of the shaft zone of the nail is more rounded.

FIG. 6 illustrates an embodiment of the surgical nail with the lateral112/medial 110 and posterior 111/anterior 116 portions of the surgicalnail more expressly shown. The posterior portion of the nail refers tothe portion of the nail directed toward the back side of the body of thepatient when the device is implanted. The anterior surface of the nailrefers to the portion of the nail directed toward the front side of thebody of the patient when the device is implanted. The shaft of the nailcan have an anterior and posterior portion that defines the positioningof the nail within the clavicle bone or other small bone, with themedial end (or proximal end) and the lateral end (or distal end)referring to the lateral side and medial side of the clavicle bone orother small bone. FIG. 6 illustrates a nail similar to the nail modeledin FIGS. 2, 3A-G, and 4A-G as it includes varying cross sectional shapesand configurations along the length of the nail device. FIG. 6 includescross sections 113, 114, 115 and dimensions labeled for an embodiment ofthe surgical nail. The specific cross sections for each zone are shown.The transitions 117 of the cross section from one portion of the nail tothe next can be seen in FIG. 6. This shows an embodiment of how oneportion of nail transitions to the next and the associated dimensionsand non-circular or circular sections of the cross section. In someembodiments, the nail can have more than one transition 117 ortransition zone. For example, the nail can include a transition zone oneither end of the shaft (as shown in FIG. 6) and/or the nail can includeone or more transition zones within the shaft zone.

As shown in FIG. 6 portions of the nail can include a cross section withat least one flat side. Certain geometries and arrangements of the flatedges can be included to provide an anti-rotational feature of the nailsystem. For example, the cross section of the distal tip portion, whichis also referred to herein as the end zone, can include four flat sidesand can have an anterior-posterior length of about 3 mm as shown in FIG.6. In some embodiments, the anterior-posterior length of the crosssection of the distal tip can be between about 2 mm to about 4 mm forsurgical nails for small bone surgery including but not limited toclavicle fracture surgery.

The flat sides of the cross section of the distal tip portion can havevarious sizes. In this embodiment, the two flats on the posterior sideof the nail may be larger or longer than the two flats on the anteriorside of the nail as shown in cross section 115. Further, as shown inFIG. 6, in some embodiments, a central portion of the shaft proximal tothe distal tip, which is also referred to herein as the shaft zone, canhave a cross section 114 that can include a 270 degree circular portionthat extends over the posterior side of the nail and a flat surface onthe anterior side of the nail. This arrangement can provide for ananti-rotational screw with a flat section in the central portion of thescrew. A first transition zone with transitional shapes as describedfurther below along its length is positioned between the distal tipportion and central shaft portion. The medial or proximal end of thenail can include a round cross section that can be configured to receivean end cap. A second transition zone with transitional cross sectionalshapes (as described further below) along its length can be positionedbetween the central shaft portion and the proximal most end of the nailwith the round cross section as shown in cross section 113. As shown inFIG. 6, the proximal or medial end of the nail can include a circular orround cross section that can be about 3 mm in diameter. In someembodiments, the diameter of the round cross section of the proximal endof the nail can be between about 2 mm to about 4 mm for surgical nailsfor small bone surgery including but not limited to clavicle fracturesurgery. For surgical nails for small bone surgery including but notlimited to clavicle fracture surgery, the proximal-distal length of thesurgical nail can be between about 100 mm to about 150 mm. Additionally,for small bone surgery for the ulna, the anterior-posterior length ofthe cross section of the nail can be between about 2 mm to about 8 mmand the proximal-distal length of the surgical nail can be between about260 mm to about 320 mm.

In some embodiments, the proximal or medial end of the nail can includea threaded screw portion. In some embodiments, the threaded screwportion can be utilized to secure the nail within the bone and/or can beconfigured to allow complementary fitting with an interior threaded endcap. The threaded end of the nail can have a shaft diameter of about2.25 mm and an outer screw diameter including the threading portion ofabout 3 mm.

The various cross-section geometries of the multiple zones of the nailas described herein can include specific round and/or flat geometries atthe distal and proximal ends of the nail and varying geometries inbetween. These various cross sectional geometries can be optimized toimprove bone impaction, achieve optimal bone engagement, and reducerotation within the bone. Zones with circular or rounded cross-sectionalareas (substantially oval, circular, smooth, minimally rounded edges notincluded) result in extensive bone impaction away from the center of thedevice and toward the periphery of the bone. The bone impaction, whilepotentially useful to create a snug fit within the bone, can create someproblems in certain areas within a small-bone nail. These problems caninclude: (1) all zones proximal to the rounded zone, unlesssubstantially larger will have reduced bone engagement due to boneimpaction created by the more distal rounded zone as it passes throughthe bone canal first; and (2) despite impacting the bone, the roundedzone is more likely to rotate within the bone as opposed to a zone withat least one flat surface.

In some embodiments, the surgical nail is arranged to allow for enhancedengagement with the bone along the length of the nail and to reducerotation of the nail. In some embodiments, all zones, with the potentialexception of the proximal most zone, advantageously contain at least oneflat surface. Additionally, in some embodiments, from the distal end tothe proximal end of the nail, all zones should either maintaincross-sectional area or increase in cross section area (with theexception of the proximal most zone). In some embodiments, some roundingof cross-sectional areas can be used moving from the distal end to theproximal end of the nail and this rounding can be achieved by simplyrounding flat surfaces away from the center line that runs along thelength of the nail. In some embodiments, the largest dimension of allzones can remain constant throughout the nail device shaft, with theexception of the proximal most zone. In some embodiments, all zones ofthe surgical nail can remain symmetrical to aid in the stability of thedevice and clarity of orientation during surgery.

In some embodiments, the most proximal zone of the nail can be a fullycircular zone in order to facilitate a threaded shaft zone and itsconnectivity with a threaded end-cap. Additionally, the nail of thisembodiment can have an added bone impaction on the proximal end. In someembodiments, the treaded end zone can be used to ease retraction of thedevice from the bone if needed. In other embodiments, the most proximalend can be made in a non-circular form and with various other end-capconnection designs.

The clavicle bone as illustrated in FIG. 2 has a gentle S-shaped curvethat varies from person to person. This S-shaped curve can make itchallenging to create a device that adapts to the S-shaped curve of thebone and facilitates insertion into the bone.

The surgical nail as shown in FIGS. 2, 3A-G, 4A-G, and 5 can have a bendthat is formed in the nail prior to insertion and/or upon manufacture ofthe nail device. The pre-bent nail can adapt to the S-shaped curve andfacilitate insertion by adding gentle curvature along a specific axis.The axis can be varied depending on the clavicle bone geometry, whetherthe nail will be inserted into the left or right clavicle, and/orwhether the nail will be inserted into the medial or lateral end of theclavicle. The curvature of the nail can be along the z-axis of the nailas shown in FIGS. 1, 2, 3A-G, and 4A-G. The curvature along the z-axiscreates a curve that goes into and out of the page. The pre-bend of thenail can have a gentle curvature that includes a gentle C-shaped orS-shaped arc to allow for easier passage and control while deploying thenail into the bone. During insertion, the surgeon can turn the C-shapedbody to direct the cutting end where desired to ease insertion andadvance the nail device into the bone.

The embodiments as illustrated in FIGS. 2, 3A-G, 4A-G, and 5 depicts twoareas of gentle curvature. The curvature can be approximately 15%-40% ofthe radius of curvature of the clavicle in each transition zone. Themore distal curvature of the nail allows for easier insertion along thecurvature of the clavicle and can be adjusted by the surgeon. In someembodiments, the nail can be bent or curved during insertion or can bepre-bent or shaped during manufacture or by the surgeon prior toinsertion. The curvature along the z-axis forms a curved nail thatcurves into and out of the page mimicking the curvature of the claviclebone. The curvature can clarify the device orientation for the surgeon.In some embodiments, the curvature can promote bending of the titaniumnail along a specific, more predictable axis due to the pre-bend of thenail. Titanium nails might naturally bend within the clavicle and thebending can be preferred to reduce rotation of the device within thebone but unpredictably bending of the nail can lead to unexpectedresults.

The size and orientation of the nail can vary depending on the desiredresults and the surgical procedure and bone fracture being treated asdescribed herein. For example, the human medullary canal of the clavicleis highly variable in shape and size, making the determination ofappropriate implant size difficult.

In some embodiments, exposure of the fracture site can be achieved witheither graduated separate drill bits in the size of the available nailsor a proprietary conical screw or awl with marks indicating the sizes ofthe nails.

End Zone:

The end zone at the distal end or first end of the nail as describedabove can have a cutting leading end geometry. With small bone surgeryand in particular clavicle bone fracture surgery it can be difficult topush medullary bone to the periphery and efficiently advance the nailthrough the curved bone without penetrating the lateral cortex. Thesurgical nail as shown in FIGS. 2, 3A-G, 4A-G can have an end-zonedesigned with: (a) slightly tapered or rounded distal tip within theend-zone that will prevent penetration of the lateral cortex; and (2) atleast one flat surface with sharp edges that meet at the tapered/roundedtip to facilitate penetration, improved surgeon control of the nailduring advancement, and increase impaction of bone. In some embodiments,the slightly tapered or rounded distal tip can be only the final distalmillimeter of end-zone along the length of the nail. In someembodiments, the end-zone of the nail can include two flat surfaces. Insome embodiments, the end-zone of the nail can have two or more flatsurfaces. FIG. 5, FIG. 7, and FIGS. 9A-B illustrate the flat surfaceswith hatch marks on the nail.

As shown in FIG. 7 and FIG. 8, the end zone 120 encompasses the tipportion of the device. The tip is the first portion of the device thatenters the bone in small bone surgery. In some embodiments, to repair aclavicle fracture the nail may enter the fractured clavicle from themedial end of the clavicle at the sternum and be advanced through thebone toward the lateral end of the clavicle. In such embodiments, thetip portion of the device is referred to as the distal tip. However, thenail may enter the fractured clavicle from the lateral end of theclavicle at the shoulder and in such embodiments, the orientation,geometry, and components described herein would be reversed. Since thenail system can enter the bone in various orientations and/or entrypoints, the ends of the nail system can be described herein as having aleading end (an end that passes through the bone first) and a trailingend (an end that is passes through the bone after the leading end). Theterminating end or leading end of the tip of the end zone is alwayssharp (non-dull) to simplify precise entry into the small bone. Forsmall bones in particular, the entry geometry (tip, cross section, andcurvature) can be important to successful and simple entry. Various endzone designs can be used. The cross section of the end zone can benon-circular. FIG. 8 illustrates cross-sections of the end zone of thedevice that can be used. The end zone design can simplify entry into thebone, as well as bone fragments that resulted from a fracture, and setupefficient placement of the rest of the device including the transitionand shaft zones. The end zone can include a cutting geometry thatcreates a path through the medullary canal of the bone.

The end zone can include a particular curvature, excluding a dull tip.The angle or curvature of the end zone can ease the insertion and/orextraction of the device. While the end zone can be curved or angled,the cross section of the end zone can remain the same throughout thezone. In some embodiments, only one side of the end zone is curved whileat least one side is flat. In yet other embodiments, the end zone can bea non-curved or straight zone. FIGS. 9A-B illustrate embodiments ofdesigns with limited or no curvature and an end zone with a tip that isnot dull. In some embodiments, the end zone can have two or more sidesthat are curved, for example in a bow structure along a specific angle.This end zone design can allow for more efficient advancement and quickplacement in the clavicle or other small bone. FIG. 9A illustrates anembodiment of an end zone with one flat edge and one curved or anglededge. FIG. 9B illustrates an embodiment of an end zone with both edgescurved or angled toward the tip. The end zone can be sectionalized toallow for bending around the curved edges within the bone. Thesectionalized end zone can include an end zone that is segmented andeach segment can move relative to one another to ease bending around thecurved edges within the bone.

FIGS. 9A and 9B show the contrast between a single flat edge with addedsharpness at the tip for easier insertion and control versus asymmetrical curved tip.

FIG. 9C shows another embodiment of a surgical nail system. FIG. 9Cillustrates the cross-sectional areas of the end zone 120, a transitionzone 121, and a shaft zone 122 that show the difference incross-sectional area between the zones and how the nail devicetransitions form one zone to the next. The end zone 120 is shown withthe sharp cutting geometry and without a large radius of curvature. Theshaft zone 122 can have flattened sides that can improve rotationalstability as described in more detail herein. Further, FIG. 9Cillustrates the use of a locking end cap 123 as well as blocking screws124 and deflecting screws 125. The blocking screw and deflecting screwcan be used to prevent migration of the nail out of the bone asdescribed herein. The blocking screw 124 can be used to physicallyprevent the nail from backing out. The deflecting screw 125 can be usedto keep the nail positioned away from the insertion site.

Transitional Zones:

In some embodiments, the nail device can include a distal end or leadingfirst end with a distinct and detailed geometry (e.g., non-rounded crosssection) and the geometry can change (e.g., cross section can increase)along the length of the nail to form a very different geometry (e.g.,round cross section) at the most proximal or trailing end. To achieve asmooth transition between the geometries of the distal or leading endand proximal or trailing end, one or more transition zones can bepresent in the surgical nail design.

For small bone surgeries, precision and control are paramount. Inaddition, the bone impaction and healing around the nail has greaterimpacts on the clinical outcome, including healing of the fracture site,usability of the bone post surgery, simplicity of nail extraction, andthe pain levels the patient might experience while the nail remainsimplanted within the patient's body. Hence, any geometric changes withinthe nail (e.g., cross-sectional areas, curvature) could complicate theprocedure, healing, stability, or device retraction. Therefore, atransition zone can be utilized as an extremely effective intermediatezone positioned in between zones of the nail device to provide forpreferred and predictable behavior during and after surgery. Thetransition zone can contain different design features and geometriesthan those present in the end zone and shaft zone. The transition zonecan provide for a gradual change between two different zones of the naildevice. The gradual change between the zones can be a minimum length of1 mm and an optimal length range of 1 mm-30 mm (although no maximumlimit on transition zone length should be applied). In some embodiments,the gradual change between the zones can be a minimum length of lessthan 1 mm. The gradual change of geometry can facilitate entry (surgeoncontrol) of the nail, maintain uniformity of bone impaction around thenail (improved rotational stability), and facilitate extraction of thenail. For example, as the nail enters the bone, the end zone (tip) firstcreates a tunnel or opening in the bone. If the nail's cross sectionalgeometry is rapidly increased, bone will push on the end zone of thethicker cross sectional geometry and prevent smooth insertion. In theopposite example, if the nail's cross sectional geometry is rapidlyreduced or changed in any axis direction (e.g., x, y, or z-axis), themore proximal or trailing portion of nail may contain space around itwhere the dimensions are smaller than the end zone. This space isextremely undesirable because it decreases rotational stability of thenail, leads to less predictable healing, and complicated extraction ofthe nail. With gentle and strategic transitions zones that are uniquelydesigned based on the geometry of the adjacent zone(s), bone contact ismaintained and outward pressure on the bone is increased at a slowerrate—achieving controllable insertion of the nail and consistent boneimpaction around the nail. Additionally, in some embodiments, thegeometry of the transition zone can have no point along the length ofthe nail that is more rounded or circular than the immediate mostproximal or trailing zone, with the exception of the transition to theproximal most or trailing most zone. This feature can be critical tomaintain uniformity of bone impaction. In some embodiments, whenrounding of cross-sectional areas occurs from distal to proximal end ofthe nail, the transition zone can be achieved by simply rounding flatsurfaces away from the center line of the nail. The center line of thenail can be defined by an imaginary line down the center of the nail andrunning through the center of the nail along its length. In someembodiments, restricting other forms of transition assists with entry,removal, and uniformity of bone impaction. In some embodiments, thetransition zones can adopt the principles of the cross sectional areasand lengths of each zone as shown in FIG. 6.

One advantageous aspect of the transition zone in some embodiments isthat it transitions the cross-sectional area of the proximal or trailingend of the end zone into the distal or leading end of the shaft zone.The characteristics that can impact the efficiency of small bone surgerywithin this zone are the length, curvature, shape, and rate of change ofthe cross-sectional area. The cross sectional area of the transitionalzone can be greater than or equal to the cross sectional area of the endzone. FIG. 10 illustrates embodiments of the cross sectional areas ofthe transitional zone.

Another advantageous aspect of the transition zone in some embodimentsis the transition of the shape of the cross sectional area within theend zone (distal or leading side of the transition zone) to a differentdesign shape within the shaft zone (proximal or trailing side of thetransition zone). As shown in FIGS. 11A-B, the transition from the sharpto flat edge cross-section of the small bone surgical nail device can beadvantageous for placement of the device within the bone. For example,as shown in FIG. 11A, the device can transition from a sharp edge to aflat edge cross-section using an intermediate cross-section thatgradually expands to flat edges on all sides of the device by havingportions with some flat edges on some of the sides as it moves from thedistal or leading end to the proximal or trailing end of the transitionzone. FIG. 11B illustrates an embodiment comprising a round or morecircular cross section for the transitional zone. In some embodiments,the round cross section of the transition zone can cause the transitionzone of the device to push the cancellous bone to the periphery andthereby not allowing engagement of the shaft zone. Therefore, in someembodiments, there is no round cross-section in the transitional zone.

Shaft Zone(s):

In some embodiments, the surgical nail can have a shaft zone with a nailbody having a cross section with at least one flat edge on the surfaceof the nail. Surgical nails for small bone surgery and clavicle fracturesurgery can have challenges related to rotational stability of thedevice. Achieving rotational stability of the device can be verydifficult to attain, for example, because of the small diameter of thebone and/or implants. Some circular or primarily rounded implants canprovide little rotational friction to aid with rotational stability. Thesurgical nail device as illustrated in embodiments in FIGS. 2, 3A-G,4A-G and other embodiments disclosed here can include, except at themost proximal or most trailing end of the shaft zone, a shaft body witha cross section with at least one flat side or edge on the nail body toaid in the rotational stability of the nail device. Additionally, thesurgical nail can maintain continuity of design between zones (end-zoneto shaft-zone and/or shaft-zone to shaft-zone). In some embodiments, theend zone shape can be substantially maintained and the flat surfaces arenot retracted but instead expanded into the first shaft zone.

The shaft zone encompasses the zone (or zones) on the proximal ortrailing end of the device, and may comprise the entire length of theshaft proximal to or trailing the end zone and the transition zone. Thedistal or leading end of the shaft zone begins at the proximal ortrailing end of the transition zone as shown in FIG. 13. The shaft zonecan be the longest zone and can be designed with specific cross-section,curvature, and proximal geometry to improve surgical outcomes. FIGS.12A-C illustrate possible cross-sectional shapes for the shaft zonearea. Various curvature lengths and angles are envisioned to maximizestrength during bending while also aiding insertion of the device intosmall bone spaces. The cross sectional area of the shaft zone can begreater than or equal to the cross sectional area of the transitionalzone. As shown in FIG. 12A, the shaft zone can comprise a flat geometryor include flat ends to prevent rotation of the bone around the implant.

FIG. 12B shows alternate cross-sectional geometries for the shaft zone.FIG. 12B illustrates cross section (a) with a standard cylindricalshape, cross sections (b) with any flat edges, cross section (c) withany convex/concave edges, and cross section (d) with any new crosssectional shape. As shown in FIG. 12C, the flat edges or convex/concaveedge of the cross sectional shape can be used to improve the rotationalstability of the device. The flat or convex/concave edge of the crosssectional shape can compact the surrounding bone improving rotationalstability and/or engagement of the shaft zone to the bone. In someembodiments, the design elements of the end zone, transition zone,and/or shaft zone can be mixed and matched with one another. The orderis interchangeable to create a broad diversity of available naildesigns, with the principles of design described herein to provide theadded functionality and control desired to improve clinical outcomes.

Locking Screw:

Nails may back out, migrate, become damaged, or cause discomfort overtime, requiring a secondary procedure to remove them. To reduce movementof the nail an optional blocking device such as, for example, a screwcan be used. In some embodiments, a unicortical blocking screw, similarto the unicortical screw illustrated in FIG. 13, can be placed justlateral/peripheral to the entry hole on the sternal side to prevent thebody of the nail from backing out of the same hole. Given thecomplication of backing out of small nails a simple blocking screw canbe used as an alternative to an end cap if an end-cap is not possible orbased on a preference of the surgeon.

The device can be used with one or more locking screws that can engagethe small bone surgical nail device and secure the device within thebone. Various forms of a locking screw(s) can be utilized to help holdthe device in place. In some embodiments, the nail device may bemodified to receive the locking screw(s). The locking screws can, forexample, engage the nail device within the shaft zone. As shown in FIG.13, the device may be adapted to receive at least one locking screw, forexample, in a plane perpendicular to the device, to lock the device inplace. For example, in some embodiments, as illustrated in FIG. 13, (a)the nail is present within the bone, (b) a unicortical hole can bedrilled in the bone and (c) a unicortical locking screw is placed in thehole to secure the nail device in place within the bone.

Traditional locking screw designs and mechanisms may also be applied. Insome embodiments, the nail device can also contain an indentation(threaded or not) to receive the locking screw. In some embodiments, theshaft zone of the device can also contain a tunnel/hole for each lockingscrew that allows the associated locking screw to pass through theentire device shaft.

In some embodiments, a locking screw 30 can be used in coordination withan end cap 20 as shown in FIG. 2, FIGS. 3A-G, and FIGS. 4A-G. Thelocking screw can be used to secure the surgical nail system in placeand prevent rotation and movement of the nail system. The locking screw30 can be inserted into a tab portion of the end cap. The tab portioncan include a proximal or trailing end extending portion extending awayfrom the end cap and an end plate portion that engages an outer surfaceof the bone. The proximal or trailing extending portion of the tab canhave an aperture that allows the screw body to pass through. Theaperture is sized to be bigger than the screw body to allow the screwbody to pass through and to be smaller than the screw head to preventthe head of the screw from passing through.

End Cap:

In some embodiments, the surgical system can include a separate end cap.The end-cap can be added to the device head (typically the proximal ortrailing end), opposite from the “end zone.” In yet other embodiments,if the end cap be used on the device tail or the “end zone.” Thesurgical nails can back out, migrate, become damaged, or causediscomfort over time, requiring a secondary procedure to remove them.The surgical nail can utilize an end cap that caps the end of the nail.The end cap can be a tabbed end cap that utilizes a second screw to keepit in place (e.g., via tabbed hole as described above), the body of theend cap itself may screw into the surrounding bone, and/or the end capcan have locking features to secure into the surrounding bone. The endcap can be tapped into the bone around the nail by the surgeon orcrimped on the nail by the surgeon. The end cap can be designed toremain at least partially submerged within the bone. The end cap can bedesigned to remain fully submerged within the bone. A submerged end capcan include a shape and/or outer surface designed to keep the devicecomfortably submerged within the bone. In some embodiments, the end capcan be a partially submerged end cap. The device with a partiallysubmerged end cap may also contain end cap geometries to allow for aportion of the end cap to be submerged in bone while the remainingportion is easily accessible on the outside of the bone. In someembodiments, the outside surface of the end cap can be or have agraduated cylinder shape, textured/rough surface to catch onto bone,tunnels or divots to catch bone, single or dual flat surface to catchbone, and/or graduate cylinder such that largest diameter is at thecenter of the end-cap (graduates up in size and then back down so theend of the cap is more easily submerged or does not stick out). As shownin FIG. 14A, the end cap 126 may be secured to the end of the nail andthe entire unit advanced into the bone.

In some embodiments, the end cap system can be manufactured as anattachment to, or connected with, the small bone nail device. Anyindividual end cap design part or feature disclosed herein can beindependently designed into the nail device directly and manufacturedsimultaneously.

In some embodiments, the end cap 126 can be configured to secure to aproximal or trailing end of nail that is threaded. In some embodiments,a surgeon can cut the nail to the desired length or a surgical kit canbe provided that includes nails of multiple sizes. The internal diameterof the distal or leading end of the end cap can be threaded to engagethe threaded proximal or trailing end of the nail.

As shown in FIG. 14B, the end cap 126 can include an extraction end capthat has a screw pitch 129 for later extraction. The end cap can becrimped or pressure welded at end 130 to the nail 128 in someembodiments, rather than being threaded into the proximal or trailingend of the nail. The crimping or pressure on the distal or leading end130 of the end cap cold welds the nail 128 to the end cap 126 whileallowing for screw extraction.

As shown in FIG. 14C, the end cap can allow for extraction by a screw-inattachment 127.

FIG. 14D illustrates alternate cross sectional geometries for the endcap. The cross sectional geometries can aid in crimping and rotationalstability.

The end-cap is designed to limit movement of the device and easeextraction after healing. The end-cap can include a cold welding design.The cold welding can be a material similar to the device to allow forcold welding and reduce galvanic effects. The end cap can have acrimping design that includes a hollow and/or divot design to allowcrimping onto the device. The end cap can include a hollow or donutdesign that is adapted to receive the device, potentially with screwthreads or shaped to receive the device head. The hollow or donut designcan include an inner surface geometry adapted to work with the deviceshaft design to facilitate placement and rotation by the surgeon. Thehollow or donut design can include a threaded inside diameter of the endcap that increases friction with the device shaft to increase rotationalstability. The design can also include a cross-sectional modificationand the inside or outside diameter of the end-cap can be variousgeometries to increase rotational control and stability. For example,the end cap can include “wings” or protrusions radially outward thatincrease rotational stability. Yet another example, the end cap caninclude spikes or other outward protrusion that enter the bone as theend cap is placed over the nail.

In some embodiments, the end cap can be made of more than one part. Forexample, a first part can contain a cylindrical shaped end cap withholes or apertures on the outer surface designed to mate with the secondpart. The second part could be a part designed to be place inside oroutside of the first part and have protrusion that enter the aperturesof the first part. Together, the two part end cap effectively holds thenail in place to prevent migration. In some embodiments, the second partof the end cap is designed to mate with the first part of the end cap,and any type of geometrical shape, or combination thereof, usable for ofeither part of the end cap. In some embodiments, the second part ispushed into the first part to snap lock the end cap system in place. Inyet other embodiments, the second part must be rotated to lock the endcap system in place. For example, the snapping or rotating can pushprotrusions or wings outward or can contain mating mechanism with thefirst part to lock the mechanism in place.

In some embodiments, the end cap system contacts the nail uponinsertion. Yet in other embodiments, no such contact is required.

In some embodiments, the end cap can include a locking feature thatsecures the end cap and nail system into the bone. The end cap caninclude a winged locking system as illustrated in FIGS. 1, 15A-D, and16A-D. FIGS. 15A-D illustrate a winged end cap 900 cylindrical in shapeand an interior threaded channel 901 running along the length of thecylindrical end cap. The end cap can have a distal or leading end 910and proximal or trailing end 920. In some embodiments, the distal orleading end 910 can be threaded and configured to attach to the proximalor trailing end of the nail. In some embodiments, a portion or all ofthe outer surface of the end cap 900 is threaded to be rotated into thebone to increase stability. In some embodiments, the general shape ofthe end cap 900 is cylindrical, yet in other embodiments, it can beconical, oval, partially rounded, entirely not rounded, or somecombination of each. In some embodiments, the proximal or trailing end920 of the end cap can incorporate the winged locking system. In someembodiments, the proximal or trailing end 920 can be used to receivingan extractor or for attaching external devices to the nail. As shown inFIGS. 15A-D, the end cap includes two wings 902 that can protrude fromwindows 903 on the surface of the cylinder of the end cap. The wings 902can move relative to the cylindrical surface of the end cap through ahinge mechanism. In some embodiments, the hinge mechanism can include apin 904 as shown in FIGS. 15A-D. The wing can have at least twopositions. The wing can have a retracted position and an extendedposition. In the retracted position, the wing can be substantially flushwith the outside surface of the cylindrical end cap. In the extendingposition, at least a portion of the wing 902 protrudes radially outwardfrom the outside surface of the cylindrical end cap as shown in FIGS.15A-D. The protruding configuration of the wing 902 can increaserotational stability. In some embodiments, the winged locking end capcan utilize a locking screw 905 that can be inserted into at least aportion of the interior threaded channel 901. FIG. 17 illustrates anembodiment of the locking screw 905 used to move the winged end cap intothe extended position. As illustrated in FIGS. 15A-D, the locking screw905 can be inserted into the proximal or trailing end of the end cap.After insertion of the nail and end cap design into the bone, thesurgical nail system can be secured in place in the bone by placing thewings 902 in the extended position. In some embodiments, the wings 902can be extended by inserting the locking screw 905 into the proximal ortrailing end of the interior treaded channel 901. As the locking screw905 passes through the channel 901, the wings are pushed into anextended position protruding from the outer surface of the cylinder.

In some embodiments, only one wing can be used. In other embodiments,two or more wings can be used. In some embodiments, the wings can beconnected to the screw or part 905 that is inserted into the part thatsurrounds the nail 920/900. In some embodiments, the wings can bedesigned as spikes, cross screws, nails, rounded or domed protrusions,ledges, pyramids, or equivalent mechanism understood by those in art. Insmall bone surgery, each additional mechanism that prevents migration isa positive. However, the level of attachment to the bone must also bereversible to a degree to allow for retraction of the device ifnecessary. In some embodiments, the wings can be closer to the nail toaccommodate limited bone between the edge of the bone and the nail. Yetin other embodiments, the wings can be placed further away from the nailto make it easier for the surgeon to activate the wings (protrude themout) as well as extract the nail by easier removal of the end cap.

In some embodiments, the hinge mechanism does not utilize a separate pincomponent but instead the movement of the wing can utilize theflexibility of the material used for the end cap. For example, in someembodiments, the wing can be a tab wing which is a cut out portions ofthe metal of the cylinder. The cut out tab wings can be cut on threesides and hinged to the cylinder on the fourth side of the rectangularwing. The cut out wing can be moved to the extended position byinsertion of a locking screw or other device that can move the cut outportion of the wing outward rotating around the connected hinged side sothat it protrudes radially outward from the outside surface of thecylinder similar to the extended position shown in FIGS. 15A-D. In someembodiments, the wings are strategically placed thickened portions ofthe end cap wall. In some embodiments, the thickened portion of the endcap wall is on the inner surface of the cap such that the wings can beprotruded into the surrounding bone by simply applying pressure on theinner surface of the end cap (e.g., with a screw or nail). In someembodiments, many layers, levels, or sizes of wings or protrusions canbe included to make the end cap more flexible for each surgery.

FIG. 16A-D illustrates several views of an embodiment of the cylindricalwinged end cap illustrated in FIGS. 15A-D without the wings, hinge, andlocking screw included. FIG. 17 illustrates an embodiment of the lockingscrew 905 used with the winged end cap and inserted into the interiorchannel of the end cap to move the wings into the extended position.

FIG. 18A-C illustrates several embodiments of the end cap designs for aclavicle nail surgical system. In some embodiments, the end cap can be acylindrical (hollow) cap that has screw threading on the inside as shownin the top embodiment of FIG. 18A-C. The screw threading on the insidecan be utilized to connect to and engage with the threads on theproximal or trialing end of the clavicle nail. In some embodiments, theend cap can have a screw threading on the outside surface of the end capto allow the end cap to sit snugly in the bone and help anchor thesurgical nail system into the bone. In some embodiments, the end cap 131can include a tab with a screw hole as shown in the embodiment of FIG.18C. In some embodiments, a screw 132 can be inserted into the tab ofthe end cap 131 to prevent migration of the nail system. In someembodiments, the end cap can have a conical, square, or rectangularcross-sectional shape. In some embodiments, the end cap can beasymmetrical in shape or include multiple cross sections shapes. In someembodiments, the end cap can include pre-fabricated cut outs or divotsto allow the surgeon to more easily cut a portion of it during surgeryto adjust to provide more optimal dimensions for each given surgery. Amarker or divot on the end cap can be used to provide a short-handmeasurement for the surgeon to see how deep the end cap is within thebone or how close the nail is to the surface of the bone. The variety ofouter shapes can provide stability by screwing into the bone and/orwedging into the bone. In some embodiments, the end cap can have variousouter shapes to provide stability by screwing or wedging into the bone.As shown in FIG. 18A, the end cap can have an outer shape that is (a)smooth, (b) spiral or treaded, or (c) angular.

The dual thread option of the end cap design as shown in the embodimentof FIG. 18B can have an interior threading with a positive thread and anegative thread. The positive thread and the negative thread havethreading rotating in opposite directions from each other. For example,in some embodiments, the positive thread can be used to attach theproximal or trailing end of the nail (with a complementary positivethread) to the interior of the end cap and the negative thread can beused to attach an extraction device or screw (with a complementarynegative thread) inside the end cap. In some embodiments, the screwinside the negative thread end of the end cap can be used to keep bonyingrowth out of the negative thread end and maintain that end forreceiving the extraction device when extraction of the end cap and/orsurgical nail system is required. In some embodiments, the sideconnecting to the nail end can have a negative thread and the sideconnecting to the extraction device or screw can have a positive end andthe proximal or trailing nail end and the extraction device and screwwill have the complementary threading. In some embodiments, the side ofthe end cap for connecting to the nail and the side of the end cap forconnecting to the extraction device or screw can both have positive orboth have negative threading and the extraction device and screw willhave the complementary threading.

In some embodiments, the nail and/or end cap can have single orgraduated pre-fabricated markings to aid the surgical procedure. Themarkings can help indicate how much of the nail has been inserted. Insome embodiments, the markings can assist the surgeon to know the bestplace to cut the nail to the desired length. In some embodiments, themarkings on the nail can have similar or corresponding marks on the endcap to assist the best and quickest placement of the end cap by thesurgeon. In some embodiments, the markings can be divots or protrusionsthat physically interact with the end cap to notify the surgeon of howfar the nail or end cap has been inserted.

The tab end cap design as shown in the embodiment of FIG. 18C is similarto the end cap design shown in FIG. 2, FIGS. 3A-G, and FIGS. 4A-G. Thetab end cap design 131 includes a flange on one side of the end cap thatincludes an aperture configured to receive a screw 132 or other securingdevice. The tab end cap can also have an interior treaded portion thatcan screw onto a complementary threaded portion on the proximal ortrailing end of the surgical nail. For example, the end cap can bescrewed and locked to the proximal or trailing end of the nail and abicortical screw 132 can be inserted through the aperture in the flangeto prevent migration.

In some embodiments, the end cap can be a tabbed end cap with a lockingscrew 1201 as illustrated in FIG. 19. In some embodiments, a separatelocking screw can be used in combination with the end cap to furtherprevent the nail system from backing out of the bone as describedpreviously. The end cap can have a screw to keep it in place (e.g., viatabbed hole), or the body of the end cap itself may screw into thesurrounding bone. The embodiment depicted in FIG. 19 can be configuredto secure to a proximal or trailing end of the nail that is threaded. Insome embodiments, a surgeon can cut the nail to the desired length or asurgical kit can be provided that includes nails of multiple sizes. Asshown in FIG. 19, the outer diameter 1202 of end-cap is also threaded todig into the surrounding bony structure when inserted into the bone. Insome embodiments, the outer diameter 1202 of the end-cap gradually canincrease in diameter along the length of the end cap from the distal orleading end to the proximal or trailing end to improve the connectivityof the end cap to the bone. In some embodiments, the tab 1203 can extendfrom the end cap and can include a screw hole 1204 to receive thelocking screw 1205 as shown in FIG. 19. In some embodiments, the tab1203 can be bendable or removable by a surgeon or other user. Thelocking screw 1205 can be inserted through the screw hole 1204 toprovide a locking mechanism and secure the surgical nail system to thebone.

The small bone surgical nail system can be used in various small boneprocedures. For example, FIG. 20 illustrates a clavicle fractureprocedure. FIG. 20 illustrates a clavicle bone with the acromialarticulation or shoulder end 133 of the clavicle and the sternalarticulation or chest end 134 of the clavicle. Cross section 135illustrates the lateral cross section which is elliptical, cross section136 illustrates the central cross section which is round, and crosssection 137 illustrates the medial cross section which is round. Theclavicle fracture procedure is illustrated with reference to steps 1through 7 of FIG. 20. Step 1 illustrates the midshaft (diaphyseal)clavicle fracture. Step 2 illustrates the incision over the fracturesite and sizing of clavicular diaphysis. Step 3 illustrates a medialincision and opening at the sternal articulation. In some embodiments,the opening can be done with a drill or awl. Step 4 illustratesadvancement of the nail through the entire clavicle. Once the nail isadvanced through the clavicle, the fracture is aligned by the nail. Step5 illustrates that the nail can be measured or sized to the desiredlength and/or cut to be flush with the bone. Step 6 illustrates theplacement of an optional end cap that can be inserted on the sternal ortrailing end of the nail. The end cap can be crimped to fix the end capto the nail as described previously or any other end cap configurationor technique described herein can be used. Step 7 illustrates theoptional placement of one or more locking screws. The locking screw canbe placed in a central region of the bone and nail as shown in FIG. 20and/or any other placement of locking screws described herein can beused.

The embodiments of FIG. 20 as well as the embodiments described withreference to other Figures describe the insertion of the nail systemfrom a sternal or medial end of the clavicle and advancing the nailthrough the bone toward a shoulder or lateral end of the clavicle.However, depending on the bone or fracture being repaired, the nail canbe entered through various positions within the body. For example, torepair a clavicle fracture, it is understood that the nail may enter thefractured clavicle from either the distal/lateral end of the clavicle atthe shoulder or the proximal/medial end of the clavicle at the sternum.Therefore, in embodiments where the nail is entered from the lateral orshoulder end of the clavicle, the nail geometry described herein can bereversed from the proximal to distal end of the nail system from thatdescribed with reference to FIG. 20 as well as other figures herein.Therefore, in such embodiments, the components and zones described onthe proximal end of the nail would be on the distal end of the nail andthe components and zones described on the distal end of the nail wouldbe on the proximal end of the nail. Additionally, in such embodiments,the end cap and lock screw can be positioned at the lateral end of thesurgical nail once inserted into clavicle. Regardless of the entry pointof the nail, the nail system is advanced through the bone from one endtoward the other end. Therefore, as used herein the description of thecomponents of the nail system can be referred to as having a leading end(an end that passes through the bone first) and a trailing end (an endthat is passes through the bone after the leading end).

As described herein, the reference to the positioning of the nail asanterior, posterior, medial, or lateral describes one orientation of thenail. However, the positioning of the nail with respect to a patient'sbody can change or flip depending on the entry point of the nail as wellas the bone the nail is used to repair. The nail system described hereincan allow for multiple entry points for entry and/or removal of thedevice as well as use in multiple small bones.

Although some details, geometries, and configurations of the device andsystem are described herein with respect to clavicle fracture surgery,the device can also be used in other types of small bone surgeries. Forexample, the device and systems described herein can be used for ulnasurgery.

All of the features disclosed in this specification (including anyaccompanying exhibits, claims, abstract and drawings), and/or all of thesteps of any method or process so disclosed, may be combined in anycombination, except combinations where at least some of such featuresand/or steps are mutually exclusive. The disclosure is not restricted tothe details of any foregoing embodiments. The disclosure extends to anynovel one, or any novel combination, of the features disclosed in thisspecification (including any accompanying claims, abstract anddrawings), or to any novel one, or any novel combination, of the stepsof any method or process so disclosed.

Various modifications to the implementations described in thisdisclosure may be readily apparent to those skilled in the art, and thegeneric principles defined herein may be applied to otherimplementations without departing from the spirit or scope of thisdisclosure. Thus, the disclosure is not intended to be limited to theimplementations shown herein, but is to be accorded the widest scopeconsistent with the principles and features disclosed herein. Certainembodiments of the disclosure are encompassed in the claim set listedbelow or presented in the future.

1. A nail fixation system, the system comprising: a nail sized forpositioning within a clavicle or other bone, the nail comprising anelongate shaft having a proximal end and a distal end, the nailcomprising multiple zones along its length having variouscross-sectional geometries; wherein: the nail comprises an end zone atits distal end having a first cross-sectional shape and a shaft zoneproximal to the end zone having a second cross-sectional shape, whereinthe first cross-sectional shape is different from the secondcross-sectional shape; the nail comprises a transition zone between theend zone and the shaft zone; the transition zone has a thirdcross-sectional shape that is different from the first cross-sectionalshape and the second cross-sectional shape; the shaft zone has a crosssectional area greater than or equal to a cross sectional area of thetransition zone and the cross sectional area of the transition zone isgreater than or equal to a cross sectional area of the end zone; and thetransition zone has a length of at least 1 mm.
 2. The system of claim 1,wherein the nail comprises an end zone at its distal end having a firstcross-sectional shape and a shaft zone proximal to the end zone having asecond cross-sectional shape, wherein the first cross-sectional shape isdifferent from the second cross-sectional shape.
 3. The system of claim2, further comprising a transition zone between the end zone and theshaft zone, wherein the transition zone has a third cross-sectionalshape.
 4. The system of claim 2, wherein at least the end zone has anon-circular cross section.
 5. The system of claim 3, wherein the endzone, transition zone, and shaft zone comprise a non-circular crosssection.
 6. The system of claim 2, wherein the shaft zone has a largercross-sectional area than the end zone.
 7. The system of claim 3,wherein the shaft zone has a cross sectional area greater than or equalto a cross sectional area of the transition zone and wherein the crosssectional area of the transition zone is greater than or equal to across sectional area of the end zone.
 8. The system of claim 1, whereinthe proximal end of the nail has a round-cross section.
 9. The system ofclaim 1, wherein the nail comprises an anterior surface sized andconfigured to face an anterior side of the clavicle bone and a posteriorsurface sized and configured to face a posterior side of the claviclebone, and wherein the nail is bent or curved toward either the anteriorsurface or the posterior surface.
 10. The system of claim 9, wherein atleast a portion of either the anterior surface or the posterior surfaceis flat.
 11. The system of claim 1, wherein the distal end of the nailhas at least one sharp edge.
 12. The system of claim 2, wherein the endzone comprises a cutting geometry configured to create a path throughthe medullary canal of the bone, the cutting geometry comprising acurvature on at least one edge of the end zone toward the distal end ofthe device configured to create a sharp distal end.
 13. The system ofclaim 1, wherein a distal portion of the nail has a cross-section withfour flat sides.
 14. The system of claim 1, wherein the nail has a firstcross-section with a plurality of flat surfaces and a secondcross-section with a single flat surface, wherein the second crosssection is proximal to the first cross-section.
 15. The system of claim14, wherein the transition zone is configured to provide at least onetransitional cross section between the first cross-section with aplurality of flat surfaces and the second cross-section with a singleflat surface.
 16. The system of claim 1, further comprising an end capat or configured to engage the proximal end of the nail.
 17. The systemof claim 16, wherein the proximal end of the nail is externally threadedand a distal portion of the end cap is internally threaded forattachment to the externally threaded proximal end.
 18. The system ofclaim 16, wherein the end cap is crimped or welded onto the proximal endof the nail.
 19. The system of claim 16, wherein the end cap comprises aplurality of retractable and expandable wings for engagement with bone.20. The system any one of claim 16, wherein a proximal portion of theend cap is internally threaded to receive a screw extractor. 21.(canceled)
 22. (canceled)